1. Field of the Art
The present invention relates to aromatic condensation compounds which form enantiomeric isomers, and more specifically it relates to novel aromatic condensation compounds useful as optically active building blocks for construction of various types of optically active substances, and to a process for their production.
2. Prior Art
Optically active substances which give enantiomeric isomers (hereunder, "enantiomers") which have a relationship often likened to that of the right and left hands, are very important in the development of medicines, foods, agricultural chemicals and aromatics. This is because the physiological activity and chemical reactivity of optically active substances is usually completely different depending on the enantiomer. For example, in the case of glutamic acid, one of the enantiomers (L-form) has flavor while the other enantiomer (D-form) has no flavor. Also, as in the well known thalidomide case, unfortunate drug toxicity was caused by the use of an enantiomer mixture (racemic mixture) including the enantiomer with teratogenicity.
Consequently, in research and development of optically active substances, it is essential to selectively obtain only one enantiomer with the desired physiological activity and chemical reactivity, and optically active substances are used exclusively for this purpose as well. For example, there are known methods wherein a separate optically active substance is added to an enantiomer mixture (racemic mixture) to form a diastereomer, and methods of separating optically active substances (optical separation) using chromatography with the optically active substance supported on a solid phase. Also, research is being ardently pursued using various optically active asymmetric reagents for the purpose of asymmetric synthesis of one optically active enantiomer and asymmetric reduction or oxidation to obtain the desired optically active substance.
A large number of optically active substances (asymmetric molecules or asymmetric compounds) have been discovered toward achieving these purposes, and attempts have also been made at their synthesis by artificial molecular design, but most of these are expected to be asymmetric based on the presence of symmetry elements, with point symmetry or face symmetry. Furthermore, most conventional optically active substances are suited entirely for specific uses, and few can provide useful units as building blocks for constructing various optically active substances. For example, no optically active substances have been found which can be expected to provide materials which function as asymmetric reduction reagents or asymmetric oxidation reagents while also being useful as pharmaceuticals and research reagents by interaction with complicated biological substances such as DNA.